Passenger vehicles employ or incorporate a multi-speed power transmission of either the manual type, that is, countershaft, or the automatic type, that is, planetary. With the advent of the desire to improve performance and economy, the number of speeds available with these transmissions has increased from two in automatic transmissions, to five or more. In manual transmissions, the number of speeds has increased from three to six or more.
Also, with the desire for improved economy, manufacturers are considering lower-displacement high-speed engines, which will provide better fuel economy, maintain the performance, and reduce the engine size. The engines being considered are apt to reach speeds of 7000 to 8000 rpm at their maximum usable level. It will therefore be incumbent to provide transmissions which will satisfy the powertrain needs for these higher speed engines.